Self-advancing mine roof support units



United States Patent Inventor Hans Rieschel Essen-Holsterhausen, Germany Appl. No. 708,843 Filed Feb. 28, 1968 Patented Sept. 15,1970

Assignee Bergwerksverband G.m.b.H. Essen, Germany a company of Germany Priority March 7, 1967 Germany SELF-ADVANCING MINE ROOF SUPPORT UNITS 7 Claims, 5 Drawing Figs.

u.s.c| 91/368, 91/411,91/46l,91/3,92/110,137/62,137163.15, 61/452 1nt.Cl. FlSb 9/10, Fl5bl3/06 [50] FieldofSearch' 91/3, 189 (Cursory), 170MP, 41 l (Cursory), 412 (Cursory), 413 (Cursory), 368, 461 (Cursory); 61/45.? [56] References Cited UNITED STATES PATENTS 2,241,330 5/1941 Shaw 91/3 2,859,022 11/1958 Frye ..9l/170(MP)UX 3,282,283 11/1966 Takeda 91/3 3,437,010 4/1969 Jacobi et al 6l/45.2

Primary ExaminerPaul E. Maslousky AttorneyMalcolm W. Fraser ABSTRACT: The specification describes a mine roof support system of the self-advancing type in which forward movement is guided by means of a jet extending forwards from a nozzle on the system and arranged to be received by pressure-responsive means mounted on a conveyor or the like in front of the system.

lllllllllll SELF-ADVANCING MINE ROOF SUPPORT UNITS The present invention relates to self-advancing mine roof support units, and more particularly to the steering of such units in a horizontal plane.-

One particular object of the invention is to provide a steering system which is robust and can be operated by fluids under pressure as are conventionally used for the control of such self-advancing units.

A further object of the invention is to provide a steering system which does not involve a mechanical linkage between the units to be steered and a fixed part such as a conveyor.

In a self-advancing mine roof support unit comprising two roof support frames each constructed for contact with a mine roof and floor, the frames having means for bracing against the roof and floor, the present invention consists in that the unit further comprises: an oblique ram extending between the rear of one frame component and the front of the other frame component, a transverse ram for connecting the frame components, steering means including two aperture means of which the first is arranged to emit a fluid jet while the second is arranged to respond to the jet and to provide a fluid-transmitted signal varying in accordance with the degree of align ment between the two jet means in a direction perpendicular to the jet, one jet means being mounted on adjacent components of the frames while the other is mounted opposite it at a position offset along the direction of travel of the unit, the jet being arranged to extend in the general direction of travel, and fluid amplifier means for controlling the relative supply of fluid to the rams in accordance with the fluid-transmitted signal of the second jet means.

Preferably the first jet means is arranged to be supplied from a fluid control circuit which serves for initiation of the first-mentioned ram and the first jet means comprises a nozzle for emitting the jet, a nozzle housing, and a pressure-operated means for moving the nozzle out of the housing in a direction of the jet.

The control circuit for initiation of operation of the ram can be of a type conventional in self-advancing mine roof support systems, for instance as described in the article by Jacobi: Automatisierung des Strebausbaus zur besseren Pflege des I-Iaengenden" in Glueckauf, page 101, 1965, Vol. 14. With such a control circuit the alternate bracing and depressurization of the frames in the unit in accordance with extension and retraction of the advancing ram can be performed automatically on the receipt of a suitable pneumatically or hydraulically transmitted signal.

In accordance with a preferred embodiment of the invention the second jet means comprises funnel-shaped cavities widening towards the nozzle.

The nozzle can be arranged to be moved by the pressure of fluid used to produce the jet.

The unit can further comprise means responding to outward movement of the nozzle and arranged to initiate operation of the circuit for advancing the frames in alternate succession. A bush with a cam surface can conveniently be arranged to be moved by the nozzle, the bush having a stroke less than that of the nozzle, and the means responding to outward movement of the nozzle being arranged to make contact with the bush. The nozzle can be provided with a valve for closing it, the valve being arranged to be opened by making contact with the second jet means.

The second jet means can include spring-loaded check valves connected with cavities opening towards the jet.

Further features and advantages of the present invention will appear from the following description.

Some embodiments of the invention are now described with reference to the accompanying drawings.

FIG. 1 is a diagrammatic plan view in accordance with the invention showing the fluid-operated control means.

FIG. 2 showsa jet producing means in section.

FIG. 3 shows a further jet producing means provided with a valve.

FIGS. 4 and 5 show two forms of jet receiving means.

In FIG. I reference numeral 1 denotes a long-wall coal face along which a coal face conveyor 2 runs. The mine roof behind the coal face is supported by means of hydraulic self-advancing support units of which each consists of two frames 3, 3a, and 3, 3b. Each frame has hydraulic means for bracing it against the mine roof in a conventional manner. The adjacent components of the two frames are connected together. The units are moved forward for the self-advancing action by means of advancing cylinders 4a and 4b which produce a resultant advancing force in the direction of arrow A. Thus resultant is directed towards a fixed point on the conveyor in accordance with the operation of fluid-operated control means to be described.

The two units are provided with hydraulic means constituting a control chain. Since this chain is conventional it is not shown in detail. It causes release of some of the frames from the mine roof so that they can be advanced by the hydraulic rams 4a and 4b and then bracing of these advanced frames so that the remaining frames can be advanced by opposite movements of the rams 4a and 4b. These advancing movements may be arranged to stop automatically once the frames have been moved through a certain preset distance. The operation of this chain is started by a pneumatic signal along an air line 6.

For controlling the advancing direction of the units we pro vide transverse rams 7 and 8 with piston spaces 7a and 8a. Transverse ram 7 is connected at its ends with frame members 3 and 3b and ram 8 with frame members 3 and 3a.

For ensuring that the units are caused to travel in the required direction in relation to the conveyor belt 2, I provide two aperture means of which one is attached to the units and the other is attached to the conveyor belt. The aperture means are arranged to emit and receive a fluid jet so that variations in the relative positions of the aperture means will cause less of the jet to be received by the cooperating aperture means. In the concrete example shown the aperture means for producing the jet is denoted by general reference numeral 9 and is fixed to the units while the second aperture means for receiving the jet is, denoted by reference numeral 10. This jet receiving means is fixed to the frame of the conveyor belt 2 and, as will appear from the following description, serves as a sort of target to which the units direct themselves during their self-advancing movements.

The first aperture means 9 includes a cylinder 11 with a piston 12 connected with a hollow piston rod 13 having a bore 14. The front end of the bore 14 begins to taper at about position 15 to a nozzle 16.

The piston rod 13 passes through a bush 18 which can be slid by the piston in a forward direction against the action of a spring 17. The front end of the bush 18 projects out of the front wall of the cylinder 11 and has a cam surface 19 for actuating an on-off valve 20. This valve, which includes a housing 21 serves to allow compressed air or other fluid medium to flow along line 5 for starting advancing of the units by means of operation of the rams 4a and 4b, such operation being accompanied by alternate bracing and depressurization of the frames 3, 3a, and 3, 3b. The duct 6 for the supply of compressed air or other pressure medium for the transmission of a signal to initiate advancing of the units has a branch line 6a, bypassing the valve 20 and leading to the rear end of the cylinder 1 l for discharge of air into the cylinder.

As soon as the compressed air signal arrives in the duct 6 the rear end of the cylinder behind the piston 12 is pressurized and the piston 12 is pushed forwards. At the same time a jet of air issues from the nozzle 16. The piston continues to move forwards until it abuts against the rear end of the bush l8 and pushes the bush forwards against the action of the spring 17 so that the cam surface 19 pushes the valve 20 to the left so that the line 5 is connected with the line 6. As a result the units begin to advance.

In the embodiment of the invention shown in FIG. 1 the second aperture means which responds to the jet comprises a block-like body 30 in which there are two groups of jet receiving apertures arranged to provide a fluid-transmitted signal varying in accordance with the degree of alignment between the jet from the nozzle 16 and the block 30. Jet-receiving means are in the form of funnel-shaped cavities 32 which have rear ends in the form of holes 31 which are closed by springloaded check valves 33. The jet-receiving means are connected in two groups which are connected by lines 34 and 35 with amplifying means 36 which are identical.

Each amplifying means comprises a diaphragm 37 which is arranged to be moved by pressure in the lines 34 and 35 as the case may be and in turn is arranged to move a push rod extending through a cavity whose wall is denoted by 38. The push rod operates two ball valves of which one is arranged to be closed by a spring 39.

The housing of the amplifier is provided with an outlet 40 and a supply inlet 41 while a further duct 42 connected with the housing leads to the ram 7a or 8:1.

The apparatus is shown in FIG. 1 in a position in which the nozzle I6 is so aligned with respect to the block 30 that there is no error signal being produced which would lead to a sufficient pressure imbalance in the rams 7a and 8a to move the frames 3 to the left or to the right. In this position the nozzle jet follows the direction indicated by the arrow A.

If, however, the frames 3, 3a, and 3, 3b are so displaced that the jet is directed towards one group of jet-receiving apertures instead of towards the other the check valves 33 in the former group of apertures will be opened by the force of the jet and a pressure signal will be transmitted by the line 34 or 35, as the case may be, to the respective amplifier 36. As a result the diaphragm 37 will be pressed backwards, that is to say away from the conveyor 2 and the ball, which is normally held against its seating by spring 39, will be opened, so that liquid under pressure can pass through the inlet 41, through the duct 42 and into the right-hand side of the ram 80 or the left-hand side of the ram 7a as the case may be, as a result that the frames are moved respectively in such a direction as to correct the displacement.

In the embodiment of the invention shown in FIG. 1 the jet of compressed air begins to emerge from the nozzle 16 as soon as the line 6 is put under pressure. This may be disadvantageous and as shown in FIGS. 2 and 3 it is possible to provide a valve to prevent this happening. As shown in FIG. 2 air arriving via line 6a enters the rear end of the cylinder 11a and pushes forward the piston 12a. As the piston moves forward against a return spring 50 and the piston rod with an axial duct 14a is moved forward. The interior of the piston rod is pressurized by a separate air line leading into a stationary tube 51 with a bore 60. The tube 51 makes sealing contact with the bore in the piston and piston rod. When the front end of the piston rod abuts against the block 30 the nozzle 56, which is provided with a flange '59, and which has a bore 57, is pushed inwards so as to move a valve ball 55 away from its seat against the action of a return spring 54 which is held in position by a collar 52 with a hollow passage 53. On this inward movement of the nozzle 56 air under pressure in the piston rod 13a is free to move past the valve and through apertures 58 at the base cavities 32 as shown in FIG. 5.

The advantage of the nozzle 56 which is extended by the action of compressed air only during advancing is that the nozzle is protected from damage during the remaining time.

I claim:

1. In a self-advancing mine roof support unit, comprising a conveyor disposed along a mine face, two roof support frames in rear of said conveyor and each having laterally spaced components and constructed for making contact with a mine roof and floor, the frames having means for bracing them against the floor and roof, the improvement that the unit further comprises: a transverse ram for connecting the components of each frame, steering means including two jet means of which the first is arranged to emit a fluid jet while the second is arranged to respond to the jet and to provide a fluid-transmitted signal varying in accordance with the degree of alignment between the two jet means in a direction perpendicular to the jet, one jet means being mounted on adjacent components of said frames while the other is mounted opposite it on said conveyor at a position offset along the direction of travel of the unit, the jet being arranged to extend in the general direction of travel, and fluid amplifier means for controlling the relative supply of fluid to the rams respectively in accordance with the fluid-transmitted signal of the second jet means.

2. A unit as set forth in claim 1, in which the first jet means is arranged to be supplied from a fluid-control circuit for initiation of operation of the rams and the first jet means comprises a nozzle for emitting the jet, and pressure-operated means for moving the nozzle outwards in a direction of flow of the jet.

3. A unit in accordance with claim 1, in which the second jet means comprises funnel-shaped cavities widening in the direction opposite the direction of flow of the jet.

4. A unit in accordance with claim 2, in which the nozzle is arranged to be moved by pressure of fluid used to produce the jet itself.

5. A unit according to claim 4, further comprising means responding to outward movement of the nozzle and arranged to initiate advancing of the unit.

6. A unit in accordance with claim 5, further comprising a cam bush arranged to be moved by the nozzle, the bush having a stroke less than that of the nozzle, and a means responding to outward movement of the nozzle for effecting advancing movement of said cam bush.

7. A unit in accordance with claim 3, further comprising spring-loaded check valves connected with cavities in the second jet means and arranged to be opened by the jet. 

